What concrete strength to assume
What concrete strength to assume
(OP)
When we only have a mix design indicating the ratio of components, such as 1:2:3 or 1:2:4 and no further information? I intend to require material testing of the existing structure to confirm, but what should I assume to start with?
I have typically taken 1:2:3 mix as being between 2500 and 3500 psi, and testing has usually found something in this range, however this project is one a tight deadline and I'm just a bit worried that I've been "getting lucky".
Any guidance anyone would care to offer? The structure in this case is a reinforced concrete bridge built in late 1930s in rural New Zealand.
Thanks,
YS
I have typically taken 1:2:3 mix as being between 2500 and 3500 psi, and testing has usually found something in this range, however this project is one a tight deadline and I'm just a bit worried that I've been "getting lucky".
Any guidance anyone would care to offer? The structure in this case is a reinforced concrete bridge built in late 1930s in rural New Zealand.
Thanks,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...






RE: What concrete strength to assume
I would keep expectations low in the 2500 to 3000 psi range, but would not be surprised to see cores over 4000 psi if all the batching variables, placement methods and inplace curing was good. - Time does wonders on some concrete.
A bridge may have had better ot tighter tighter controls, but can only go so far if there are not options.
Only testing will determine what kind of animal your have to deal with. On a lighter note, are there Wambats in New Zealand?
RE: What concrete strength to assume
this might help (the website has a lot of free documentation too that might help). just keep in mind that you're dealing with 70+ year old concrete.
http:/
RE: What concrete strength to assume
Could you do some "non-destructive" testing to get a ballpark?
RE: What concrete strength to assume
I was hoping someone would have a resource for an indication regarding proportionate design to reliable assumed concrete strength, even though I'm experienced enough to know better than to think a design-reliable assumption is possible not knowing w/c ratio or anything about the aggregates (both fine and course).
I own a copy of the mix design text from CPCA, but unfortunately it's in Canada...
Oh, and No, New Zealand does not have Wombats. That's Australia.
Cheers all,
I'll update when I know the core results,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...